This work investigates the influence of V-shaped riblets on skin friction drag reduction of transitional and turbulent boundary layers under zero pressure gradient. High fidelity eddy resolving simulations are used to demonstrate the efficacy of riblets. The riblets are represented using the Boundary Data Immersion Method (BDIM). In this paper, we validate the BDIM framework on two test cases: flow past a circular cylinder and minimal span channel with sinusoidal roughness. Subsequently we report the results on a transitioning boundary layer under the influence of free stream turbulence. The role of riblets is analyzed through the boundary layer integral parameters and skin friction coefficient. Time and span averaged turbulent statistics are presented in discerning the influence of riblets close to the wall. Analysis of flow statistics over a single riblet element is also performed through time and phase averaging. The efficacy of riblets in delaying the onset of turbulent breakdown and reducing skin friction drag is demonstrated through averaged and instantaneous flow quantities. © 2022, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.